Piston



June 12, 1945, H. H. FREEMAN PISTON Filed Feb. 23, 1944 r zfm/A f 4; Q INVENTOR.

Patented June 12, 1945 UNITED STATES PATENT OFFICE PISTON Herbert B. Freeman, Minneapolis, Minn.

Application February 23, 1944, Serial No. 528,524

2 Claims.

My invention relates to an improvement in histons for internal combustion engines, altho applicable. too, to steam engines, and the object of said invention is to permit pressure from the combastion chamber oi such engines to be introduccd into the packing-ring grooves of such engine pistons in such manner as to press the packing-rings firmly against the engine cylinder walls, as shown in the accompanying drawing-in which like numerals refer to like parts throughout the drawing, in which Fig. 1 is a plan or top view, and Fig. 2 a side elevation, partly in section, of my invention; Fig. 3 is an enlarged sectional view of Fig. 2 to show more clearly the rotation of pressure-plug 6 to exhaust. Fig. 3 is an enlarged view or port channel 2 showing a snug-fitting but freely movable pressure-plug I, the inner, or channel end of said plusbeingtaperedtopermitfree oi'compressed air to the ring-grooves below. The purpose of this plug 5 is to limit and confine the pressure against the inner surface of the packingring to the area of such plugend and not permit pressure to seep around the entire inner circumference of the r1118 5..

I claim:

1. In a piston having a port or ports connecting the cylinder combustion chamber with packing-ring grooves in said piston, a movable plug in said port or ports by means of which the application of compression chamber pressure to the inner surface of piston packing-rings is limited to an area approximatelyEthat of a cross section of said plug.

2. A piston having ports or channels connecting the cylinder combustion chamber with the packing-ring grooves of such piston in such manner that any pressure in said combustion chem-- CERTIFICATE OF CORRECTION, Patent No. 2,578,076. June 12, 19!;

HERBERT H, FREEMAN.

It is hereby certified that error appears in the printed specification of the above num er patent requiringoorreetion as follows: Page 1, first column, line 15, for "rotation" read --relation--; and that the said Letters Patent should be read wiflm'this correction therein that the same may conform to the record of the ease in the Patent Office.

Signed and sealed this 15th day of November. A. D. 1915.

Leslie Frazer (Seal) First Assistant Commissioner of Patents. 

